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Phone Charging in Caving Huts

Some nights in the Croydon cc hut in Ystrafellte weve found a dozen or so phones festooned from every socket in the building (which is a bit pointless as there is no signal there!) and the issue has been raised as to whether to try and stop this due to the fire risk .We are thinking of having having a red painted ammo box on the wall which you can put the blazing phone in and then throw out the window - some airlines are going to do something like this (but obviously not throw it out the window !) . The question I need to know is should the lid be clamped down ? would this put the fire out through lack of oxygen or would it continue to burn and burst the box open?-chris crowley
 

Bob Mehew

Well-known member
First LiPo battery fires are not conventional fires as you alluded. They don't consume oxygen from the air as they are a very fast release of all the energy which has been stored in the battery. The concern is that the released energy in the form of heat then starts a fire in material close by (including the plastic of the phone). So a far bigger risk is the fact you have all these phones all around the hut. If you want to minimise the risk, then set up a facility where the phones can be charged isolated from one another and from the rest of the hut. So if one does go off, it does not impact on the others and perhaps more importantly does not set fire to the hut. I am presuming you do have fire alarms and fire doors? (If not, you have much bigger risks which should be dealt with. One club recently was threatened with a legal notice to cease use whilst they brought their hut fire precautions up to the legal requirements.)
 

wormster

Active member
A bunker box with a whole load of pyromet in the bottom and a 6 way power strip is n an RCD would be my minimum setup.
 

andrewmcleod

Well-known member
Some nights in the Croydon cc hut in Ystrafellte weve found a dozen or so phones festooned from every socket in the building (which is a bit pointless as there is no signal there!) and the issue has been raised as to whether to try and stop this due to the fire risk .We are thinking of having having a red painted ammo box on the wall which you can put the blazing phone in and then throw out the window - some airlines are going to do something like this (but obviously not throw it out the window !) . The question I need to know is should the lid be clamped down ? would this put the fire out through lack of oxygen or would it continue to burn and burst the box open?-chris crowley
The answer is almost certainly no - you shouldn't try and stop people charging their phones (at least for this reason).

The time spent worrying about it is almost certainly better spent worrying about almost anything else - like the current quality of your wiring and if it is regularly tested, whether you have appropriate in-date smoke alarms in every room, whether you only have modern gas equipment and CO alarms, whether all your furniture is appropriately fire-resistant, whether your emergency lighting works, whether the mesh grilles in any cooker ventilation hoods are clean, whether the toaster is free of crumbs...

With the brief (and exciting) exception of the Samsung Note 8, phones just don't catch fire at any regularity (and even with those you still had to be pretty unlucky for anything to go wrong, let alone a catastrophic problem). We've all got phones plugged in at home left on overnight without managing to burn the place down...

If an electrical device is going to catch fire, I strongly suspect it's far more likely to be a charger than a phone - whether that's a phone charger or a headlight charger or whatever. Also, if something does catch fire, it's more than likely there isn't someone supervising it to chuck it anywhere anyway, plus you don't want to be handling it if it does - you want an extinguisher.

I suspect the danger due to an extra trip to the hut to set up some sort of phone-fire-box would exceed the benefit (since driving is genuinely dangerous).
 

Rob

Well-known member
". . . . a bit pointless as there is no signal there!"
If only phones could be used for other things, like taking cave photos...

But in all seriousness, i was impressed last weekend to see the YSS festooned with double mains sockets with built in USB outlets. This would reduce the risk of people using their own (Chinese knock-off) chargers.
 

andrewmcleod

Well-known member
But in all seriousness, i was impressed last weekend to see the YSS festooned with double mains sockets with built in USB outlets. This would reduce the risk of people using their own (Chinese knock-off) chargers.
I've seen that in a few huts now - one of the married rooms in SWCC for example, and I think some of the plugs in the main room of the Belfry (where there's a little phone charging shelf thing).
 

Ian Ball

Well-known member
Oops! Shows how out of touch I am. Is it Lifepo cells which are 3.2V nominal and so are at risk if charged on a 4.2 V charger for LiIon cells?
 

ChrisJC

Well-known member
No. Li-Ion and Li-Po are more or less the same from a charging perspective. And any made up pack will have a protection circuit to prevent over-voltage, over-current and over-discharge. They work on a constant voltage charge (4.2V), where the current reduces when the cell is full.
A NiCd / NiMH has a totally different voltage and charge method - you put in a constant current, monitoring the voltage rise. When the voltage stops rising, the cell is charged.

I would say that putting an NiCd / NiMH cell in a charger for Li-Po /Li-Ion would be the most exciting combination.

Chris.
 
The hut has 6 fire/smoke/gas alarms and 7 extinguishers of various types , has recently been rewired etc and an outside shed with loads of sockets for lamp charging etc but people don` t seem to want to leave them out there . We are also getting rid of the gas cooking next month . I once found a rather warm lap top on charge 'hidden' in their sleeping bag !
 
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